1. Field of the Invention
The invention relates to a controller for a vehicle AC generator for use in a vehicle.
2. Description of the Related Art
A controller for a vehicle AC generator of this kind controls the on/off state of field current passed through a field coil in response to the voltage of the vehicle AC generator and controls the generator voltage of the vehicle AC generator. A voltage controller disclosed by JP2002-95297A includes switch means that controls field current, a control circuit that controls the on/off state of the switch means in response to the voltage of the generator, a power supply circuit for the control circuit, and a voltage controller having a power supply driving circuit that drives the power supply circuit.
A semiconductor integrated circuit is generally used for such a controller for a vehicle AC generator, and for achieving reduced power consumption, a CMOS logic circuit as a CMOS semiconductor integrated circuit is used. The CMOS logic circuit is a complementary MOS integrated circuit including a P-channel MOS transistor and an N-channel MOS transistor. The controller for the vehicle AC generator using such a CMOS logic circuit must be examined for the operation of the CMOS logic circuit in an initial test before its actual operation, and in the initial test, long aging time is necessary in order to detect initial failures in the CMOS logic circuit.
The initial test is carried out to test the function of the semiconductor integrated circuit, while a short term function test does not clarify functional failures in the CMOS logic circuit and therefore aging for a long period is necessary. A power supply circuit in a controller for a vehicle AC generator in general is formed to output a signal power supply voltage for example as the power supply circuit disclosed by JP2002-95297A and can output only the single power supply voltage. The power supply voltage is output as a single power supply voltage having the same voltage value when the controller is actually operated or in an initial test state, and therefore the aging time is particularly prolonged in the CMOS logic circuit when the aging is carried out in the initial test.